Lift apparatus



Dec. 30. 1969 H. E. sczHALLr-:R

LIFT APPARATUS 4 Sheets-Shen?l 1 Filed Nov. 2, 1967 BY MAQ/@MM ATTORNEK Dec. 30, v1969 H. E. SCHALLER LIFT APPARATUS 4 Sheets-Sheet 2 Filed Nov. 2, 1967 wf/@Md Dec. 30, 1969 H, E.. SCHALLER .n 3,486,649

LIFT APPARATUS Filed Nov. 2, 1967 4 Sheets-Sheet 3 INVENTOR. HaraZcZ E Scaler' BY W W lA'TTORZVEY v Dec. 30. 1969 Hys. scHALLER LIFT APPARATUS 4 Sheets-Sheet 4 Filed NOV. 2. 1967 United States Patent O 3,486,649 LIFT APPARATUS Harold E. Schaller, East Aurora, N.Y., assignor to John E. Smiths Sons Co., Division of Hobam, Inc., Buffalo, N.Y., a corporation of New York Filed Nov. 2, 1967, Ser. No. 680,074 Int. Cl. B65g 65/36, 67/48 U.S. Cl. 214-314 Claims ABSTRACT 0F THE DISCLOSURE Background of the invention The present invention relates to an improved hydraulically actuated lift apparatus for selectively raising a cart from ground level to a dumping position and for duming its contents into an associated machine and then returning the cart to ground level. y

In the past, various types of lift apparatus were utilized to lift a cart from ground level to a dumping position and thereafter return the cart to its original position. However, these prior types of apparatus were characterized by being fabricated from specialized parts which could be replaced or repaired only with great diliiculty. In addition, in prior types of lift apparatus it was generally difficult and time-consuming to make adjustments. Furthermore, many types of previous apparatus were not universal in their application in that they were' restricted for use with a single type of load-carrying cart and could not be adapted for use with many different types. Also, in certain types there was usually no provision for jarring the load-carrying cart when in its' dumping position and therefore the load frequently stuck to the cart. In other types, where there was a load-jarring me'cahnism, it was usually expensive in that it required'specializedequipment for'l effecting the jarring action and also' required extra' heavy duty components to withstand the impact of the jarring. It is with-'an improved hydraulically actuated lift apparatus which overcomes all of the above enumerated shortcomings that' the present invention is concerned.

Summaryof the invention It is accordingly one object of the present invention to provide an `improved hydraulically actuated lift assembly for lifting a load-carrying cart from a receiving position to a dumping position rapidly so that the rapid stopping of the load in its elevated position causes the load to be totally discharged because of the momentum imparted thereto by the rapid lifting, thereby insuring complete dumping without utilizing special jarring equipment or extra heavy-duty components which must be associated with such equipment.

Another object of the present invention is to provide an improved hydraulically actuated lift apparatus which is fabricated from generally available standard components which are readily replaceable; which is fabricated in such a manner that all parts are readily accessible for replacement or repair; which includes a plurality of adjustment which render the device universal for accepting different sizes of load-carrying containers; and which includes a Patented Dec. 30, 1969 ice plurality of minor adjustments which permit the apparatus to be adjusted for extremely accurate operation.

A further object of the present invention is to provide an improved hydraulically actuated lift apparatus which includes its own hydraulic circuit and an automatic control associated therewith for providing a predetermined sequence of operations thereby automatically causing rapid lifting, dumping, and returning of the load-carrying cart to an initial position without requiring any skill on the part of the operator other than placing the load-carrying container into operative engagement with the lift apparatus. Other objects and attendant advantages of the present invention will readily be perceived hereafter.

The improved hydraulic lift apparatus of the present invention comprises a frame including a pair of spaced legs mounted on feet, with link means for attaching said frame to an associated piece of apparatus. Journals mounted at the tops of the legs receive an elongated rockshaft having a central portion secured to the piston of a piston and cylinder arrangement, the cylinder being xedly secured to the frame. Keyed to the rockshaft are a pair of downwardly extending arms which, in turn, have cart-carrying portions secured to their lower ends. An arm couples the piston of the piston and cylinder arrangement to the rockshaft and this arm is relatively short so that whenever the piston and cylinder are energized, there will be a third-class type of lever action obtained which will cause the cart-carrying arms to move extremely rapidly. However, at the end of movement the arms are stopped abruptly so that the momentum imparted to the load in the cart will cause such load to be thrown away from the sides of the cart and thus be completely discharged, without utilizing any specialized type of jarring or bumping apparatus for jarring the cart in its elevated load-dumping position. The various legs, arms and cart-carrying portions of the arms all have adjustments associated therewith for varying the spacing between the cart-carrying portions, the elevation of the cartcarrying portions, and the elevation of the frame so as to cause the lift apparatus to be universally adjustable, thereby permitting a single unit to readily accommodate dierent sizes and types of carts. In addition, the various parts of the frame and cart-lifting arms are fabricated from standard parts that can be replaced or repaired rapidly and easily.

A control circuit is associated with the lift apparatus so as to cause the dumping achieved thereby to be fully automatic; that is, the load-carrying cart need merely be placed in operative connection with the cart-carrying arms, and after an electrohydraulic circuit is energized, it automatically lifts the cart, holds the load in lifted position for a predetermined period of time, and thereafter returns the cart to a position wherein it can be withdrawn from the lifting apparatus. The present invention will be more fully understood when the following portions of the specification are read in conjunction with the accompanying drawings wherein:

l Brief description of the drawings FIGURE 1 is a side elevational view of the improved lifting apparatus of the present invention with a loadcarrying cart in operative engagement therewith;

FIGURE 2 is a plan view of the apparatus of FIG- URE 1;

FIGURE 3 is an end elevational view of the apparatus, with certain portions omitted in the interest of clarity, taken substantially in the direction of the arrows 3-3 of FIGURE 1;

FIGURE 4 s a schematic hydraulic circuit diagram for the apparatus;

FIGURE 5 is a schematic electrical diagram of the control circuit for the apparatus; and

3 FIGURE 6 is a schematic diagram showing the lift in its cart-receiving position and in its dumping position.

Description of the preferred embodiments The improved hydraulically actuated lift apparatus 10 of the present invention includes a frame 11 consisting of spaced legs 12 secured, las by welding, at their lower ends to plates 13 which in turn are secured by bolts 14 to channel portions 16 and to plate 15 which spans the space between legs 12. Feet 17, in the nature of resilient vibration pads, include threaded stems 18 extending upwardly therefrom which are received in suitable apertures, not shown, in lower legs 19 of channels 16. By the use of nuts 20 the legs 12 may be raised or lowered above the floor 21 to cause the lift 10 to accommodate different sizes of carts. To fasten frame 11 to an associated machine into which the material in the cart is to be dumped, straps 22 and 23 are provided. Straps 22 are secured to the webs of channels 16 by bolts 24 and webs 23 are secured to legs 12 by bolts 25. U-bolts 26 secure straps 23 to rods 27 which are rigidly attached to the machine associated with lift 10. For adjustability, straps 22 and 23 can have a plurality of different holes (not shown) for receiving U-bolts 26 at different positions along their length.

The upper ends of legs 12 are fastened to each other by tie rod 28 (FIG. 3) which extends through suitable apertures in the web portions of channel-shaped legs 12 and is secured thereto by nuts 29 on the opposite sides of said web portions. Tie rod 28 stabilizes the upper portion of legs 12 against movement relative to each other during load-lifting.

Secured to the upper portions of legs 12, as by welding, are journal housings 30 carrying bearing liners (not shown), which receive unitary shaft 31 which extends between and beyond journal housings 30 and is supported thereby. Mounted in encircling relationship to the central portion of shaft 31 between journals 30 is a sleeve 32 which is secured to shaft 31 by bolts 33 and 34 which are placed at right angles to each other, as shown best in FIGURES 2 and 3. The ends of sleeve 32 are relieved to receive bronze sleeves at 35 for preventing moisture from entering between sleeve 32 and shaft 31. Thrust washers 36 are located at the ends of sleeve 32 for taking up the end thrust between said sleeve and the sides of journal housings 30. To prevent undesired end play in shaft 31, collars 37 are secured to shaft 31 by set screws (not numbered) and these collars are brought up into tight relationship with the sides of journal housings 30 opposite to thrust washers 36. The foregoing assembly locates shaft 31 against undesired endwise movement relative to the journal housings 30.

Spaced container-lifting arms 38, which are essentially channel sections (FIG. 2), include collars 39 secured to their upper portions, as by welding. Collars 39 in turn are keyed to shaft 31 by keys 40 which are retained in position by set screws (not shown) extending through the collars and pressing against said keys and by additional set screws, not shown, extending at an angle of approximately 90 degrees to the first set screws in engagement with the keys. In addition, collars 41 are secured to shaft 31 by means of set screws (not numbered) for further holding collars 39 in position by bearing against the outer sides thereof.

The distance between arms 38 may be adjusted by loosening the various screws associated with collars 39 and 41 to loosen collars 39 for axial movement on shaft 31 and thereafter manipulating nuts 42 associated with ti-e rods 43 extending between the webs of channel-shaped arms 38. The elements which were loosened are tightened after arms 38 have been moved to their desired adjusted positions. By adjusting the distance between arms 38, the lift apparatus l0 can accommodate carts of different Widths.

Secured to theV lower portions of arms 38 are cartreceiving portions 44 which include channel members 45 and slotted members 46 secured thereto 'by nuts and bolts 47 extending through suitable apertures (not shown) in portions 45 and which are received in slots 48 in portions 46. This permits portions 46 to be moved axially relative to portions 45 to adjust the location of the end 49 of slot 50 relative to arms 38. In addition, portions 45 are secured to arms 38 by means of nuts and bolts 51 which extend through suitable apertures in arm 38 and are received in slots 52 in portions 45. This permits each portion 45 to be adjusted vertically in arms 38 to compensate for lloor pitch. Portions 45 have lan angle 53 (FIG. l) secured thereto as by welding for receiving bolts 54 which bear against the leg of channel 38 to impart torsion resistance to arm portions 45.

It can readily lbe seen that arm portions 46 can be adjusted relative to arm portions 38 to accommodate different sizes of carts or containers and furthermore arm portions 46 can be adjusted to different elevations relative to each other to compensate for an evenness of oors, if required. Thus, arm portions 46 which receive the cart can be adjusted in .a plurality of different directions by either elevating the frame by adjusting nuts 20, or by varying the spacing between said arm portions by adjusting tie rods 43 and collars 39, or by manipulating bolts 47 and 51.

The container or cart 55 is of a capacity to carry 466 to 600 pounds of a product and includes a pair of central Wheels 56 and single end wheels 57. It will be appreciated that when cart 55 is being pushed by a person grasping handle 58, it will ride on both wheels 56 and either one of wheels 57. Secured to the sides 59 of the cart are lugs or pins 60 and angle members 61. In order to place cart 55 in engaging relationship with arm portions 46, it is merely necessary to wheel the cart between said arm portions, as can best be seen in FIGURE 2. Initially, lugs 60 will ride up on cam portions 62 of arm portions 46 and thereafter ride through slots 63 located between bifurcations 64 and 65 until such time as they reach depressed portions 49 of slots 63, as can vbest be seen from FIGURE l, at which time they will fall into said portions and be retained therein. At this time the front wall 65 of the cart is located in its desired position adjacent the front wall 66 of chute 67. As noted above, for containers or carts which are of a different length, arm portions 46 can be moved in and out relative to arm portions 45 to provide the necessary orientation between cart 55 and chute 66.

Chute 67, in addition to including a front wall 66, also includes side walls 67 and outwardly extending flared edge flanges 68 and 69. The front wall 66 has straps 69 secured thereto, as by welding, and these straps include portions 70 which receive bolts 71 for securing said straps to the legs of the channel-shaped arms 38. Chute 67 serves to direct the contents of cart 55 into the machine associated with the lifting apparatus 10. In other Words, it essentially provides an extension of front wall 65 of the cart.

In order to raise arms 38 from their cart-receiving dotted-line position shown in FIGURE 6 to the solid-line position for dumping, an hydraulic motor 72 consisting of a cylinder 73 and a piston 74 is provided. The lower portion of cylinder 73 is attached -by clevis 74 to bar 75 secured between legs 12 by bolts (not shown). Bar 75 also rigidizes legs 12 relative to each other against relative movement. The piston 74 is attached by clevis 76 to one end of arm 77, which is rigidly secured to sleeve 32, as by welding. It is to be especially noted that arm 77 is extremely short and this will cause the arm portions 46 which carry cart 55 to whip upwardly rapidly whenever piston 74 moves upwardly in FIGURE 1. This fast movement will provide a relatively large momentum to the contents of cart 55 and when it is stopped abruptly in its elevated solid-line position shown in FIGURE 6, the m0- mentum of the contents will cause them to leave cart 55 without clinging thereto. In this manner, complete emptying of the cart is obtained without the necessity of an accompanying jogging, jarring or knocking of the cart 55 in its elevated position. Thereafter the cart is returned to its loading position shown in FIGURE 1 in a fully automatic manner.

After the cart 55 has been placed in position shown in FIGURE 1, dumping can commence b y closing the start switch 80, thereby complementing a circuit from L1 to L2 via lead 81, stop switch 82, lead 83, start switch 80, lead 84, electric motor 85 and lead 86. This will also ignite indicating light 87 which is placed in Iparallel across motor 85. At this time it is to be noted that motor 85 and an hydraulic -pump 88 (FIGURE 4) are housed within housing 89 mounted on plate 15 secured to legs 12. Housing 89 also includes a sump 90 (FIG. 4). The completion of the foregoing circuit also causes the energization of up solenoid 91 through leads 92 and 93, normally closed timer contact 94, and leads 95 and 96. As can be seen from FIGURE 4, this will cause hydraulic uid to flow from pump 88 via conduit 97, valve conduit 98 and conduit 99 to the lower portion of cylinder 73 while permitting the upper portion to be exhausted to sump 90 through conduit 100, valve conduit 101 and conduit 102, As soon as hydraulic motor 72 is energized in the foregoing manner, arms 38 will start traveling in a clockwise direction in FIGURES l and 6. After a small amount of travel, switch arm 103 of switch 104 will lose engagement with arm 38, switch 104 being mounted on one of legs 12. This will cause switch 104, FIG. 5, which is open when arms 38 are in the position shown in FIG. l, to close thereby completing a holding circuit to motor 85 via lead 105, switch 104, switch 106, motor contacts 107 which are closed when the motor is running, and means 92 and 84 and 86. This will maintain motor 85 in operation after switch 80 is opened on being released. The arms 38 will travel in their clockwise direction under the driving force of motor 72 until such time as they reach their uppermost position shown in solid-lines in FIGURE 6. At this time arm 108, which is secured to collar 39 and therefore will rotate with shaft 31, will engage switch arm 109 of limit switch 110, switch 110 being mounted on the upper portion of leg 12. Normally open limit switch 110 (FIG. 5) will be closed to complete a circuit through relay 111, through lead 112, switch 110, and leads 113 and 114. The energization of relay 111 will also cause a holding circuit across switch 110 to 4be maintained by the closing of contacts 115 which are placed in parallel across switch 110 by leads 116 and 117. The timing 'relay 111, which is thus energized, will then time out after a predetermined period of time and thereafter open the normally closed switch 94 to thereby break the circuit to up solenoid 91 and simultaneously close normally open switch 118 to complete a circuit through down solenoid 119 through lead 120, switch 11-8, and leads 121, 122. This will cause the solenoid valve to shift to a position which will establish a flow of hydraulic fluid to conduit 97, valve condiut 123, and conduit 100 to the upper lportion of cylinder 73, while at the same time permitting exhaust of the lower part of cylinder 73 through conduit 99, Valve conduit 124, and conduit 102 to the sump 90. Piston 74 will move downwardly to rotate arms 38 in a counterclockwise direction until such time as arm 103 of limit switch 104 is engaged to open this switch in FIGURE 5. This will open the circuit to motor 85, thereby also opening relay contacts 107. The opening of switch 104 will also terminate the ow .of current to timing relay 111 which on deenergization will cause switches 94 and 118 controlled thereby to return to the position shown in FIGURE 5 placing the up solenoid in condition for subsequent energization upon the closing of limit switch 104.

A suitable throttling valve 125 is associated with pump 88 to control the flow therefrom and suitable throttling valves 126 and 127 are provided to control the rate of flow to the lower and upper portions of cylinder 73, respectively.

While the lift apparatus 10 has been shown as including a combined motor pump unit 89, it will be appreciated that the motor and pump may be a part of the associated apparatus relative to which the lift apparatus 10 is mounted, such associated apparatus -being shown in my copendng application Ser. No. 651,922, filed July 7, 1967.

I claim:

1. A lift apparatus comprising a frame including a pair of spaced legs, a rockshaft, journals mounted on the upper portions of said spaced legs for pivotally mounting said rockshaft, a lever arm extending from said rockshaft, an hydraulic motor having a first end xedly mounted relative to said legs and a second end secured to said lever arm, a pair of spaced arms, means securing said spaced arms to outer ends of said rockshaft, with each of said arms including a downwardly extending portion and a substantially horizontal cart-receiving portion secured to said downwardly extending portion, adjustable feet secured to said spaced legs for raising and lowering said frame, first adjustment means for moving said arms toward and away from each other, and second adjustment means for adjusting the positions of said horizontal cart-receiving portions relative to said downwardly extending portions of said arms.

2. A lift apparatus as set forth in claim 1 wherein said rockshaft includes a single shaft extending beyond said legs for mounting said arms, a sleeve encircling the central portion of said shaft between said journals, and means aflixing said sleeve to said rockshaft for rotation in unison, said lever larm being affixed to said sleeve.

3. A lift apparatus as set forth in claim 2 including first movable collars affixed to said shaft on the opposite side of said journals from said sleeve to securely hold said shaft centered on said legs, and second movable collars aixed to said shaft on the opposite sides of said arms from said rst collars.

4. A lift apparatus comprising a frame including a pair of spaced legs, a rockshaft, journals mounted on the upper portions of said spaced legs for pivotally mounting said rockshaft, a lever arm extending from said rockshaft, an hydraulic motor having a first end Xedly mounted relative to said legs and -a second end secured to said lever arm, a pair of spaced arms, means securing said spaced arms to outer ends of said rockshaft, with each of said arms including a downwardly extending portion and a substantially horizontal cart-receiving portion secured to said downwardly extending portion, control means for actuating said hydraulic motor for rotating said arms to an elevated dumping position and returning said arms to a cart-receiving position comprising a start switch, electric motor means, ,an hydraulic pump coupled to said electric motor means, rst solenoid valve means, rst relay means for energizing said first solenoid valve means for causing flow of hydraulic fluid to said hydraulic motor from said pump upon the energization of said start switch to thereby move said arms to said dumping position, a first microswitch mounted on said frame, means on said arms for energizing said rst microswitch when said arms reach said dumping position, circuit means coupling said microswitch to said relay means for maintaining said rst solenoid valve means energized for a predetermined period of time while said arms are in said dumping position, second solenoid valve means, said circuit means including means for deenergizing said first relay means and said iirst solenoid valve means after said predetermined period an also including second relay means for energizing said second solenoid valve means to effect a flow between said pump and said hydraulic motor for returning said arms to a cart-receiving position, and a second microswitch on said frame for deenergizing said control circuit Iafter said arms .return to said cart-receiving position.

5. A lift apparatus as set forth in claim 4 wherein said lever arm is extremely short so that said piston and cylinder occupy a generally vertical position when said cart-receiving portions are in cart-receiving position so as to provide a rapid lift rate to said arms.

6. A lift apparatus as set forth in claim wherein said hydraulic motor comprises a piston and cylinder mounted substantally parallel to said legs and centrally therebetween, and wherein said rockshaft includes a single shaft extending beyond said legs for mounting said arms, a sleeve surrounding the central portion of said shaft between said legs, and wherein said lever arm is secured to said sleeve, means rigidly aflxing said sleeve to said shaft against relative rotation, a bar extending horizontally between said legs, and wherein said cylinder includes a portion pivotally mounted on said bar, and wherein said piston is pivotally secured to said lever arm.

7. A lift apparatus as set forth in claim 6 including adjustable feet secured to said spaced legs for raising and lowering said frame, rst adjustment means for moving said Varms toward and away from each other, and second adjustment means for adjusting the positions of said horizontal cart-receiving portions relative to said downwardly extending portions of said arms.

8. A lift apparatus comprising a frame including a pair of spaced legs, a rockshaft, journals mounted on the upper portions of said spaced legs for pivotally mounting said rockshaft, a lever arm extending from said rockshaft, an hydraulic motor having a rst end ixedly mounted relative to said legs and a second end secured to said lever arm, a pair of spaced arms, means securing said spaced arms to outer ends of Saidrockshaft, with each of said arms including a downwardly extending portion and a substantially horizontal cart-receiving portion secured to said downwardly extending portion, said hydraulic motor comprising a piston and cylinder mounted substantially parallel to said legs and centrally therebetween, said rockshaft including a single shaft extending beyond said legs for mounting said arms, a sleeve surrounding the central portion of said shaft between said legs, said lever arm being secured to said sleeve, means rigidly aixing said sleeve to said shaft against relative rotation, a bar extending horizontally between said legs, said cylinder including a portion pivotally mounted on said bar, said piston being pivotally secured to said lever arm, said lever arm being extremely short so that said piston and cylinder occupy a generally vertical position when said cart-receiving portions are in cart-receiving position so as to provide a rapid lift rate to said arms, said legs comprising first channel members and said arms comprising second channel members, adjustable to tie rod means extending between said arms, and means for movably securing said arms to said single shaft to adjust the distance therebetween.

9. A lift apparatus as set forth in claim 8 including means for adjustably mounting said cart-receiving portions of said arms relative to said downwardly extending portions of said arms to compensate for floor pitch.

10. A lift apparatus as set forth in claim 9 including means for adjusting the length of said cart-receiving portions of said arms.

References Cited UNITED STATES PATENTS 2,268,220 12/1941 Marshall 214-314 2,626,071 1/1953 Smith 214-314 2,822,113 2/1958 Joiner 214-314 2,905,344 9/1959 Hostetler et al. 214-314 HUGO O. SCHULZ, Primary Examiner 

